1. Field of the Invention
The invention is directed to pumps, and more particularly to an improved geared feed pump.
2. Description of the Prior Art
One known geared feed pump known from German Patent Disclosure DE 196 38 332 has a housing, in which a pump chamber is formed between a housing part and a cap part. A pair of gear wheels that mesh with one another on their outer circumference are disposed, such that they can be driven to rotate, in the pump chamber. The gear wheels pump a feed medium from an intake chamber, communicating with a tank, into a pressure chamber, along feed conduits formed between the circumference of the gear wheels and circumferential walls of the pump chamber. The pump chamber is defined by the cap part, which is located opposite the face ends of the gear wheels and which is meant to rest as tightly as possible against the face ends of the gear wheels, so as to achieve secure sealing of the feed conduits and thus good efficiency of the geared feed pump. On the other hand, however, some play in the direction of the pivot axes of the gear wheels between their face ends and the cap part is necessary, to assure that the gear wheels can be driven to rotate with little friction. The requisite play must be assured even when the geared feed pump is being put together, and furthermore, because of heating during operation of the geared feed pump, this play varies, especially when the gear wheels on the one hand and the housing part and the cap part on the other are of different materials.
The geared feed pump of the invention has the advantage over the prior art that by means of the cover element, secure sealing of the feed conduits is achieved, and a requisite play in the direction of the pivot axes of the gear wheels can be established counter to the initial tension of the cover element.
In one embodiment of the invention the initial tension of the cover element is generated in a simple way. In another embodiment, feed medium and/or air can be positively displaced out of the indentation upon the motion of the cover element into the indentation.